Carbon and nutrient cycles

The ocean plays a dominant role in the Earth’s carbon and nutrient cycles. These cycles are intrinsically linked together and sustain life in the ocean and form a key part of our climate system.

Our long and internationally recognized track record in biogeochemical cycling aims to quantify key processes in the cycling of life sustaining elements in the upper ocean and coastal seas. We use an interdisciplinary approach to study the cycling of carbon and nutrients at interface of biology, chemistry and physics from the sea-surface to the sea-floor. We investigate processes that transform Carbon and nutrients as these are transported from land to sea and across the sea-air interface.

Recent research has concentrated on the pathways, reactions and transformations of nitrogen, carbon and sulphur through the marine biogeochemical system. Particular highlights have been: quantifying ocean acidification across the Atlantic Ocean over the last 20 years; quantifying the impacts of ocean acidification on biogeochemical cycles; quantifying the impacts of multiple stressors upon micro-organisms in the surface ocean, and investigating the impact of variable ratios of micro-nutrients (e.g. iron and zinc) to macro-nutrients (e.g. nitrate and phosphate) on ocean productivity.

We are also investigating the cycling of organic compounds, and our research in this area has focused on the large and complex dissolved organic fraction within seawater and its role in providing microbes with energy, nitrogen and sulphur. Until recently our understanding of the sources, sinks and reaction pathways of ubiquitous organic compounds, such as methanol, osmolytes containing nitrogen, acetone and acetaldehyde was very limited. However, research campaigns studying seasonal cycles and ocean basin variability have allowed us to start unravelling their significance in meeting organic carbon requirements and supporting microbial metabolic processes.

Making a difference

A thorough understanding of carbon and nutrient cycles is essential to enable us to understand how the ocean functions and may respond to future environmental and climate change and will help to improve predictive tools for policy makers and other stakeholders.

Scientists have discovered that Antarctic krill – a tiny shrimp-like crustacean – plays a key role in fertilising the Southern Ocean with iron, which stimulates the growth of phytoplankton, the microscopic plants at the base of the marine food web.

Microscopic plastic pollution, which is present throughout the world’s seas, could affect the feeding habits of one of the ocean's key inhabitants – the copepod; a tiny animal with a highly important role within marine food webs.